Quench, or quench and temper, metallurgical processes are widely used to harden, or harden and temper, a manufactured metal product such as steel pipe, to achieve desired metallurgical and mechanical properties different from those of the starting material used to produce the metal product. Quenching is done after heating of the product, for example, by electric induction heating. Open spray quenching systems are one type of quench systems that can be used to accomplish the hardening and tempering of the metal product. When in-line quenching round, square, rectangular or other shaped products, such as pipes, bars or tubing, at production line speed, an important parameter that determines the material properties achieved by these processes is the metal cooling rate, which must generally be as fast as is possible to obtain the desired results. The cooling rate is determined, in part, by the volume of quenchant used during the rapid cooling of a heated metal part and the velocity of quenchant at the metal surface. The traditional apparatus used to provide a high volume flow of water to the surface of a heated part is sometimes known as a quench barrel. The typical quench barrel is a large diameter, monolithic cylinder equipped with a multitude of holes or nozzles through which quench media flows under medium pressure. Upon contact with the heated metal part, the quenchant provides the rapid cooling necessary to obtain a desired hardness. Also well known is the fixed position quench ring or slot quench. This apparatus is a hollow ring through which the part to be quenched passes. The apparatus contains a multitude of equally spaced holes or slots that act as nozzles for the quenching fluid. The slot quench is typically used in single part, small volume applications, such as induction hardening scanners.
There also exists spray quench apparatus, such as U.S. Pat. No. 2,657,698 where a spray outlet passage is formed between inner surface (34) of radial flange (15) and inner surfaces (31) and (32) of insert (17) and annular casting (27), respectively, as shown in FIG. 2 of U.S. Pat. No. 2,657,698. Flange (15) terminates in a sharp edge 16 that extends in a generally axial direction corresponding to the direction of the workpiece travel. Annular casting (27) also extends in the axial direction corresponding to the direction of workpiece travel and terminates in edge (33).
Quenching systems must be capable of treating a range of product diameters. However, existing quench barrels and quench rings have a fixed inside diameter. When products having different diameters pass through these fixed diameter devices, the shape of the spray impinging on the product, the spray flow rate, and spray pressure change due to the difference in gap between the spray nozzles and the product. For existing quench systems when the spray is reflected from the product for a given nozzle, the reflected spray can interfere with the spray pattern of adjacent nozzles, and diminish or even destroy their effectiveness. The above limitations of existing quench systems can also cause expanding steam to form at the surface of the product to be quenched. This creates a thermal steam barrier that greatly reduces the rate of cooling of the product.
Further the small “pin hole” quench nozzles used to create the water jets in existing barrel quench systems limit the effective spray volumes and pressures that can be achieved.
Additionally since the product typically must move through the quench device both linearly and while rotating, the supporting conveyor rolls are skewed relative to the axis of travel of the product. This causes different diameter product to run on different centerlines through the conventional fixed geometry quench systems.
It is an object of the present invention to overcome the above limitations of existing spray quench systems.
It is another object of the present invention to provide a spray quench system where the quench rings in the spray quench system are coordinated with the type of quenchant supply to the quench rings to change the pressure, quench ring exit velocity, flow rate, and/or pattern of the spray quench from the outlets of the quench rings in the spray quench system.
Other objects of the present invention are illustrated by the aspects of the invention set forth in this specification and the appended claims.